Microbiological and biochemical quality of grouper (Epinephelus chlorostigma) stored in dry ice and water ice

The changes in the microbiological and biochemical quality of grouper (Epinephelus chlorostigma) stored in dry ice (solid carbon dioxide) were investigated. Fresh fish stored in dry ice at the ratio of 1:1 (wt/wt) were found to be organoleptically suitable for consumption when they were stored for 30 h without re‐icing. Fish stored in water ice (as control) at the ratio of 1:1 (wt/wt) and in a combination of dry ice and water ice at the ratio of 1:0.2:0.5 (wt/wt/wt) were acceptable up to 18 and 24 h, respectively. Total bacterial load ranged from 10⁵ to 10⁷ CFU g^?1, while total psychrophiles from 10³ to 10⁶ CFU g^?1. Total lactics were found in the levels of 10²–10⁴ CFU g^?1. Total volatile basic nitrogen contents were within the limit of acceptability in all the three treatments, whereas trimethylamine nitrogen content exceeded the limit (15 mg%) and hypoxanthine content was 11.11 mg (100 g)^?1 on the 30 h in grouper stored only in dry ice. Lowest temperature of ?5.8 °C was recorded in grouper stored only in dry ice. Hundred percent CO₂ environment within the package was found in grouper that were stored in dry ice and combination of dry ice and water ice.